1. Field of the Invention
The present invention relates to an image forming device which provides user services of the printer function, the copier function, the scanner function, the facsimile function, etc., and more particular to the memory management of such image forming device.
2. Description of the Related Art
In recent years, the image forming device in which the respective functions of the printer, the copier, the facsimile and the scanner are installed in the same equipment is known. Hereinafter, the image forming device of this type will be called a multi-function machine. The multi-function machine is provided with three kinds of software corresponding to the printer, the copier, and the facsimile, respectively, and operates the equipment concerned as the printer, the copier, the scanner, or the facsimile by changing the software from one to another. Moreover, the multi-function machine is provided with the display, the printing unit, the image reading unit, etc. that are installed in the same equipment.
The conventional multi-function machine is configured by preparing separately the programs corresponding to the printer, the copier, the scanner, and the facsimile functions, respectively. The memory areas needed by the processes created by the execution of the respective programs are assigned separately. The total size of the memory areas assigned for the respective processes becomes large according to the size of each program.
On the other hand, the memory management is performed by the operating system (OS) when the programs, such as the copy, the scanner and the printer of the multi-function machine, are running on the OS. Usually, the memory management by the OS has taken the architecture in which the memory areas are managed on the basis of one page of a fixed size in many cases.
For this reason, there is a significant difference in the size of the memory areas used according to the programs of the multi-function machine and the size of the memory areas used according to the memory management by the OS. Hence, there is the problem in that the processing speed becomes slow by the overhead in the case of the memory access due to the difference, and the memory use efficiency deteriorates.
With the conventional multi-function machine, it is configured by preparing separately the software (the general-purpose OS being included) corresponding to the printer, the copy, the scanner, and the facsimile functions of the multi-function machine, respectively, and the development of each software takes great time.
For this reason, the image forming device should have the hardware resources used by the image forming processing of the display unit, the printing unit, the image reading unit, etc. The image forming device should be provided with a plurality of applications which perform the processing respectively specific to each user service of the printer, the copy, or the facsimile. And the image forming device should have the platform which is interposed between the applications and the hardware resources, and include various control services which perform management of hardware resources needed in common by at least two applications, the execution control, and the image forming processing being offered.
When the user service is offered, it is requested that the image forming device is equipped with the above platform which includes the various control services. While attaining the increase in efficiency of the software development by considering as the composition equipped with the platform which performs the above-described functions, it becomes possible to raise the productivity as the whole equipment.
It is desirable that the above-mentioned characteristic composition can be effectively used for the memory management, because the software which is executed by the multi-function machine includes a plurality of applications and a plurality of control services.